Noshok 25-400-300-psi/kg/cm2-ST5 1/4 NPT Bottom Conn, 2.5 Stainless Steel Gauge, 0.5 mm SS Threaded Orifice

The NOSHOK 25-400-300-psi/kg/cm2-ST5 is a 2-1/2″ all-stainless steel dry gauge for 0–300 psi. It has a 1/4″ NPT male bottom connection, a psi/kg/cm² dial, and a 0.5 mm stainless steel threaded orifice.

Part number:

• 25: Dial size.
• 400: All-stainless bottom-connection case.
• 300: Range of 0–300 psi.
• psi/kg/cm2: Dual scale.
• ST5: 0.5 mm stainless steel threaded orifice.

The orifice size is the key detail. NOSHOK offers stainless threaded orifices in 0.8 mm (ST8) and 0.5 mm (ST5). The smaller 0.5 mm passage restricts flow more, so it damps pressure pulsation more heavily than the ST8. That makes it a good choice for a dry gauge on a pulsating line, where there is no liquid fill to steady the pointer. Because the orifice is stainless, the entire wetted path remains stainless.

The kg/cm² secondary scale (about 0–21 kg/cm² at 300 psi) suits equipment and documentation from regions that still specify that unit. At 300 psi, the gauge uses a 316 stainless steel C-type Bourdon tube, which the 400 Series applies up to 600 psi.

Series specifications:

• Accuracy: ±1.6% of full scale for 2-1/2″ models.
• Media temperature (dry): −40 to 392 °F.
• Case: 304 stainless steel with a safety relief plug.
• Lens: Trogamide.
• Dial: UV-resistant aluminum.

Typical applications include reciprocating pump discharge, compressor lines, chemical dosing and process water. The 400 Series is suited to these services because its corrosion-resistant construction holds up where brass internals would not.